The preparation of shaped extruded food products from a slurry of comminuted foods is well known. For example, in U.S. Pat. No. 3,650,766 a method for the preparation of such shaped products is disclosed which involves the preparation of a slurry of comminuted foods including a gel-forming material which gels upon exposure to a gelation solution. The slurry is extruded into a desired shape through an extrusion nozzle which, in all material respects, is quite similar to conventional donut-forming apparatus. The resulting shaped product is then subjected to a bath or spray of gelation solution to form a skin or envelope which maintains the structure of the shaped product during further processing such as coating, freezing, baking, frying, and the like.
Conventional apparatus for the preparation of such products is disclosed in U.S. Pat. No. 3,814,560. Typically, such apparatus comprises an extrusion head and a cutter-plate or disc which cooperate to define an extrusion nozzle, and a cutter-sleeve. The cutter-plate and sleeve are movable relative to each other so as to cut off successive extrusions from the extrudable slurry of comminuted food particles which is forced through the extrusion head. Such apparatus also includes means for periodically charging the head with the extrudable slurry so as to form the successive extrusions at the nozzle. Where, as noted above, the extrudable slurry includes a gel-forming material which is gelable upon exposure to a gelation solution, the shaped extruded product is typically dropped into a bath which contains the gelation solution thus serving to form a gelled skin about the product which holds the product together during further processing. As described in detail in U.S. Pat. No. 3,814,560, the extruded product will normally be carried through the gelation or setting bath on a conveyor which will then continue to carry the extruded product through further processing stages such as battering, breading, frying, etc.
Due to the rather fibrous nature of the food products which may be incorporated into various products made according to the above technique, the severing of successive extrusions at the extrusion nozzle is often incomplete and a "hinging" effect is experienced. Specifically, in the case of extruded onion rings or clam strips, for example, a small piece of onion or clam can often get caught between the cutter-plate and cutter-sleeve thereby preventing immediate and complete severance of the extruded shape at the nozzle. This effect is particularly pronounced where there is an excess clearance between the cutter-plate and sleeve which can be caused by wear on the cutter-sleeve over extended periods of usage. The result of such "hinging" is that the desired spatial orientation of the product with respect to the extrusion head, as it leaves the nozzle and drops onto the conveyor belt for passage through the setting bath and on for further processing, will not be maintained and thus the product will drop onto the belt in a deformed shape or will be deformed upon contact with the belt. Further, complete severance may not be obtained at all thus resulting in multiple extrusions which are physically connected together. In order to avoid these problems, it has heretofore been necessary to have production personnel present at the extruder to manually separate the pieces from each other, and, where the effect cannot be avoided, to remove the deformed products, or "cripples" as they are known in the art, from the conveyor prior to further processing. In fact, the state-of-the-art today is such that available extrusion apparatus operates at speeds of up to 300 strokes per minute giving as many as 6 extrusions per second, thus making inspection and manual correction difficult tasks to accomplish.
It is therefore an object of the present invention to provide an improved method and apparatus for preparing shaped extruded food products which avoid the problem of "hinging" presently encountered by existing apparatus, and do so in a manner which avoids the need for production personnel to manually correct the problem.
It is a further object of the present invention to provide an improved method and apparatus for preparation of shaped extruded food products which will serve to maintain a predetermined spatial orientation of the shaped product with respect to the extrusion head after severance of product at the extrusion nozzle such that "hinging" of the product will be avoided.
It is still a further object of the present invention to provide an improved method and apparatus for the preparation of extruded food products which serve to maintain the shape of the extruded product while the product is maintained in a predetermined spatial orientation with respect to the extrusion head after severance at the nozzle.